This invention relates to a process for the preparation of water-soluble vinyl saccharide polymers which have utility, for instance, as polymeric thickeners for aqueous solutions and as water treating agents.
The publication "Entwicklung neuer Polymertypen zur Tertiarforderung von Erdol" (Forschungsbericht 165-2, 1982) of the Deutsche Gesellschaft fur Mineralolwissenschaft and Kohlenchemie describes the preparation and performance of water-soluble vinyl saccharide polymers. Two alternatives are disclosed for the preparation of such polymers: (1) polymerization of a vinyl ester of a monosaccharide, in which the pending hydroxyl groups have been protected, in the presence of a free-radical initiator followed by treatment with acid to liberate the hydroxyl groups to render the polymer water-soluble, or (2) polymerization of a water-soluble vinyl ester of a monosaccharide in water and in the presence of a hydrogen peroxide, potassium persulfate, or ammonium persulfate free-radical initiator. Although the products of these polymerizations are said to be characterized by a relatively high viscosity, it is found that such methods are not suitable for the preparation of materials having viscosities sufficiently great to be useful in many commercial applications. For example, tests have shown that these methods do not produce water-soluble polymers which as a one percent by weight solution in water have a viscosity greater than 2.0 Pa.s at 25.degree. C.